I've flown out of MCO a few times, although it's been since November of 2010 since my last flight. Why doesn't MCO have a separate line for first class and elite F/F passengers.

I know that MCO caters more towards leisure and family flyers, relative to other airports of its size. Yet, MCO also has a lot of convention business, both at the convention center and at various hotels at or near Disney World. Those are business passengers, and probably a number of them are road warriors with elite status.

By the same token, LAS also caters to a large number of leisure flyers and people coming in for conventions. I've been in Vegas during a Teamsters convention and a hardware show convention. LAS has security lines for first class and elite F/F passengers.

So, what is the rationale for not having first class/elite F/F at MCO?

Well at a guess I would say not enough First or Elite F/F complain about it to their airline.
From the airports point of view there is nothing in it for them to start up a new line and divert resouce from the already long lines. I pass in/out of MCO 6 times a year and always expect, and get a wait time of about 20+mins.
If more poeple raised this as a concern with their airline perhaps they might fund an Express line, airport company sure anit gonna pay for it.

Did you know that MCO operates "CLEAR" which gets you past the security line in 5 mins.

I never have had any problem with MCO security. If you go through the expert traveler line, and know what you're doing, you're going to be through in less than 5 minutes. At the same time, if you have those people in front of you that think they are experts, but they really aren't, then you might have to wait ten or more minutes. I go through that line every time I fly through MCO, usually 10 times per year, and usually at different times during the day, morning, noon, and night. So try that line.